For many years, surgical treatments (operations) for human beings have relied on a physician visually examining a target portion and performing necessary treatments, such as retracting or resecting the target portion, by manually utilizing a scalpel or other surgical tools.
However, the targets of operations have been smaller in size and finer in structure in accordance with the accumulation of biological and anatomical information relating to the target organs and the improvement of the medical techniques. Meanwhile, the progress in electronics has enabled the creation of an imaging system that is smaller in size yet higher in resolution, with a satisfactory level of color-reproducing capability that allows the system to be used in the actual treatments. As a result, endoscopic surgical operations have been widely performed in recent years, in which an image of the inside of the body taken through optical fibers is displayed on a large screen and a physician manipulates a surgical tool while watching the screen.
Efforts have also been made in searching for a method of remotely manipulating a tool by means of a manipulator, and a variety of specific methods have been proposed. For example, Patent Document 1 discloses a system for driving a manipulator having a built-in endoscope. In this system, the manipulator is operated through a control stick or voice recognition unit.
Patent Document 2 discloses a point-lock system in which an insertion hole formed in a body wall is utilized as the supporting point for a rod-shaped manipulator to minimize the invasion to a patient. In this system, an operator wearing a face mounted display (FMD) drives a treating manipulator through an operation input device while visually checking an image projected on the FMD. The motion and position of a viewing manipulator are controlled according to the motion of the physician's head detected by a three-dimensional digitizer provided in the FMD.
Patent Document 3 discloses a system with a manipulator support mechanism especially designed to reduce the burden on the operator. Accordingly, in this system, the operator needs to directly operate the manipulator. The endoscopic image is displayed on an external screen.
Non-Patent Document 1 discloses a method of controlling a surgical tool having three light-emitting points on the side of its tip. Based on an image of these three points, the distance between the internal irradiation point (laser spot) of the laser light emitted from the tip of the surgical tool and the tip of the same tool is determined, and the surgical tool is controlled so that the distance will be at a predetermined value.    Patent Document 1: Japanese Unexamined Patent Application Publication No. H06-030896    Patent Document 2: Japanese Unexamined Patent Application Publication No. H08-215205    Patent Document 3: Japanese Unexamined Patent Application Publication No. 2003-052716    Non-Patent Document 1: A. Krupa, et al., “Autonomous 3-D Positioning of Surgical Instruments in Robotized Laparoscopic Surgery Using Visual Servoing”, IEEE Trans. on Robotics and Automation, Vol. 19 (2003), No. 5, pp. 842-853